Gas turbine burners having a central fuel distributor element and swirl generators enclosing the fuel distributor elements are described for example in DE 10 2007 004 394 A1, US 2004/0055306 A1 and U.S. Pat. No. 6,082,111. In the burners described in US 2004/055306 A1 and U.S. Pat. No. 6,082,111 the swirl generator extends in each instance from the central fuel distributor element to a wall enclosing the central fuel distributor element and bounding an axial flow channel for combustion air. The burners here each comprise a number of such arrangements. In such burners the profiles of the fuel injected into the flow channel are designed such that only very little fuel is fed to the zone around the central fuel distributor element, so that only a very lean mixture forms in this zone. This is with the intention of preventing flashback. A zone with reduced flow speed therefore results in the vortices, which form on the downstream side of the central distributor element. If too much fuel is now injected in proximity to the central distributor element, it may happen that this central region with low flow speed is supplied with too much fuel, which can result in flashback, which in the event of large loads is associated with very high temperatures downstream of the swirl generator. By diminishing the quality of the mixture, the very lean mixture in the region of the central fuel distributor element causes an increase in NOx emissions, which however have to be tolerated to prevent flashback.
To prevent flashback it is proposed in DE 10 2007 004 394 A1 that the swirl vanes should be provided with cutouts in proximity to the central fuel distributor element, so that the swirl vanes in proximity to the central fuel distributor element are shorter in an axial direction than those some distance from the distributor element. The curvature of the swirl vanes in a circumferential direction therefore does not extend so far in proximity to the central distributor element as it does some distance from the central distributor element. This means that the air flowing through the flow channel is subject to less swirling in proximity to the distributor element and therefore flows faster in an axial direction than it does further away from the distributor element. A cylindrical wall can also be present in the region of the cutout on the inner edges of the swirl vanes facing the distributor element, separating the channel segment with less vortex formation from the channel segment with greater vortex formation.